It is generally known to produce various mechanical parts of a gas turbine from a Ni-based heat resistant alloy. For example, heat resistant alloys having the following compositions in mass % are known as the Ni-based heat resistant alloy that constitutes the various mechanical parts: a Ni-based heat resistant alloy composed of 19.5% of Cr, 13.5% of Co, 4.3% of Mo, 1.4% of Al, 3% of Ti, 0.6% of C, 0.05% of Zr, 0.006% of B, and a balance of Ni; Ni-based heat resistant alloy composed of 19% of Cr, 11% of Co, 9.8% of Mo, 1.5% of Al, 3.2% of Ti, 0.09% of C, 0.07% of B, and a balance of Ni; a Ni-based heat resistant alloy composed of 19% of Cr, 12% of Co, 6% of Mo, 1% of W, 2% of Al, 3% of Ti, 0.03% of C, 0.007% of B, and a balance of Ni; and Ni-based heat resistant alloy composed of 16% of Cr, 8.5% of Co, 1.8% of Mo, 2.6% of W, 1.8% of Ta, 0.9% of Nb, 3.5% of Al, 3.5% of Ti, 0.11% of C, 0.05% of Zr, 0.01% of B, and a balance of Ni.
The various mechanical parts of a gas turbine composed of the Ni-based heat resistant alloys are produced through welding. A welding wire having a composition composed of, in mass %, Cr: 18 to 22%, Co: 10% or less, Al: 0.2 to 0.7%, one or two selected from Ta, Mo, and W: 15 to 28%, C: 0.09% or less, Zr: 0.06% or less, B: 0.015% or less, Ma: 0.4 to 1.2%, Si: 0.2 to 0.45%, and a balance of Ni and unavoidable impurities is provided as an example of a wire for welding the Ni-based heat resistant alloy. It is described that this wire for welding Ni-based heat resistant alloy can be subjected to TIG welding or MIG welding under a room temperature, that is, without preliminary heating the parts to be repaired, and the weld zone has excellent ductility, satisfactory oxidation resistance, and high-temperature tensile strength and creep resistance that fulfill the requirement (Patent reference 1: Japanese Unexamined Patent Application, First Publication No. 2001-158929).